Views: 0 Author: Site Editor Publish Time: 2026-08-08 Origin: Site
At LIUZHOU IRON & STEEL CO., LTD, slag removal from cyclone wells had long been carried out by manually operated overhead cranes. The working environment was harsh, with high humidity, elevated temperatures, and corrosive acidic gases containing sulfur compounds, all of which posed serious health risks to operators. During heavy fog in winter or at night, visibility was severely limited, frequently resulting in "blind grabs" that caused collisions with the slag pool. When water levels were high, operators struggled to determine slag depth, leading to frequent empty grabs. The monotonous nature of the work also contributed to fatigue and safety incidents. In addition, the legacy system provided no operation logs, no weight records, and no fault history, making process management largely data-blind.
To address these challenges, LIUZHOU IRON & STEEL engaged Wuhan Forward Technology to deploy a fully unmanned crane system, upgrading the entire operation from manual handling to end-to-end automation. This overhead crane automation retrofit project represents a significant step forward in steel mill automation, demonstrating how modern industrial crane automation can solve long-standing operational problems in demanding environments.
The unmanned cyclone well slag handling system is built around six proprietary technologies independently developed by Wuhan Forward: high-precision Gray code positioning, anti-sway control, laser radar 3D scanning, mobile operation terminals, 3D management and dispatch software, and an intelligent scheduling algorithm. All subsystems communicate seamlessly with one another, delivering a complete automatic slag removal solution for steel mill applications.
High-precision Gray code positioning. Gray code positioning is applied along both the bridge and trolley travel paths, delivering a resolution of 1mm and an accuracy of 5mm. The system operates without physical contact, resists corrosion, and is well-suited for harsh outdoor conditions. Grab height and open/close status are fed back in real time via absolute encoders, ensuring reliable X-, Y-, and Z-axis measurement data. This crane positioning technology is fundamental to the system's ability to execute precise, repeatable automatic slag grabbing operations.
Anti-sway control. Due to the flexible nature of wire ropes, the grab inevitably swings during crane motion. The anti-sway controller eliminates over 95% of oscillation, achieving a positioning deviation of ±25mm and a sway angle accuracy of ≤±0.4°. This not only prevents the grab from striking pool walls but also shortens the waiting time for load stabilization. Crane anti-sway technology is a core enabler of safe and efficient unmanned crane operation in steel mills.
Laser radar 3D scanning. Laser radar systems scan the slag pool and transport vehicles to generate 3D models, automatically calculating optimal grabbing and dumping points. The scanning unit is equipped with a protective dustproof housing that retracts automatically after each scan, significantly reducing lens contamination and the frequency of high-altitude maintenance. This 3D scanning capability enables the unmanned grab crane to adapt to changing material conditions in real time.
Mobile operation terminals. These terminals support three operating modes—fully automatic, semi-automatic, and manual remote control—with switching available from the central control room, ground cabinets, or onboard panels. This flexible control architecture ensures that manual intervention remains possible during maintenance or abnormal conditions.
3D management and dispatch software with intelligent scheduling. The platform provides real-time 3D visualization, displaying equipment position, operational status, and alarm notifications. The built-in intelligent scheduling algorithm automatically optimizes the grabbing sequence based on different material conditions: for dry slag, it prioritizes high-density areas before transitioning to a grid pattern to prevent uneven loading and cable damage; for wet slag, it skips low-density zones and concentrates on productive areas for higher efficiency. The system also logs every grab operation with coordinates, weight, and time-stamped records, supporting historical playback and production statistics.
Multi-layer safety protection. A three-tier collision prevention strategy is implemented, including soft limit protection, deceleration limits, and mechanical travel limits. Door interlock switches activate audible and visual alarms when access is attempted during automatic operation. Overload protection triggers a warning at 90% of rated capacity and stops hoisting motion at 100%. Dynamic torque balancing on dual motors prevents cable slack or entanglement.
After commissioning, actual production data demonstrated tangible improvements:
Personnel safety. Operators have been entirely removed from hazardous zones, eliminating exposure to corrosive gases and high temperatures. Safety incidents related to crane operation have dropped to zero.
Operational efficiency. The combination of precision positioning and anti-sway control reduced the average grab cycle time by roughly 15–20%, while the empty-grab rate fell from over 10% to below 1%. This crane automation retrofit delivered immediate productivity gains.
Equipment protection. The three-tier anti-collision system and active sway suppression have eliminated grab impacts with pool walls. Wire rope service life has extended by approximately 30%, thanks to balanced load distribution and reduced off-angle pulling.
All-weather operation. The system runs continuously and stably around the clock, unaffected by fog, nighttime conditions, or rain and snow.
Data-driven management. All operational parameters are automatically recorded, providing a reliable foundation for performance assessment, preventive maintenance, and process refinement.
With the deployment of Wuhan Forward's unmanned cyclone well slag handling system, LIUZHOU IRON & STEEL has effectively resolved long-standing issues including hazardous working conditions, inefficient blind grabbing, and a lack of operational transparency. The result is a safer, more productive, and intelligent steel mill automation solution. This overhead crane automation case study demonstrates how advanced technologies—Gray code positioning, anti-sway control, and laser radar 3D scanning—can be integrated into a unified unmanned crane system that delivers measurable results in demanding industrial environments. The system has since been adopted by multiple steel mills, validating its reliability and practical value.
